Utilization of renewable solar energy is crucial for addressing the global energy and environmental concerns and achieving sustainable development. In this regard, photocatalytic water splitting has attracted significant interest as a cost-effective means to convert sustainable solar energy into valuable chemicals.

However, because efficiency is sensitive to reaction conditions and experimental setup, it is difficult to compare the results obtained by different research groups or provide a reliable guide for large-scale implementation. Due to the lack of testing standards, it is difficult to compare the results obtained by different research groups or provide a reliable guide for large-scale implementation.

A research team led by Prof. LI Can and Prof. LI Rengui from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS), in collaboration with Prof. Kazunari Domen from The University of Tokyo, Prof. Lianzhou Wang from The University of Queensland, Prof. Kazuhiro Sayama from the National Institution of Advanced Industrial Science and Technology, and Prof. Gang Liu from the Institute of Metal Research, CAS, has now initiated the establishment of international efficiency accreditation and testing protocols for particulate photocatalysts toward solar fuel production.

Efficiency accreditation and testing protocols for particulate photocatalysts toward solar fuel production. Credit: DICP

Photocatalytic water splitting has attracted great interest as a means of cost-effective conversion of sustainable solar energy to valuable chemicals. However, the absence of authorized efficiency measurement methods results in the accumulation of unverifiable and often misleading data, wasting the investment and resources of the research community and impeding the progress in the research field. Herein, testing protocols for reliable efficiency reporting of photocatalytic overall water splitting are discussed based on particulate photocatalysts.

The sources of error and standard reporting protocols for hydrogen evolution rate, light source calibration, and solar-to-hydrogen (STH) efficiency have been revisited and recommended. The establishment of accreditation research laboratories is proposed for efficiency certification toward the launch of the figure of merit, a “best research photocatalyst efficiencies” chart.

This initiative will provide an important platform for establishing standard testing protocols in photocatalytic water splitting and accelerating the STH conversion efficiency improvement toward practical application.

—Wang et al.

Their perspective, published in Joule, is expected to serve as a useful guide for developing a well-recognized testing standard and for further promoting research advances in the field of photocatalytic solar energy conversion.

The researchers discussed the protocols for the reliable determination of the efficiency of the overall photocatalytic water splitting reaction based on particulate photocatalysts.

They also proposed to establish accreditation research laboratories for efficiency certification toward the launch of a figure of merit—a “Best research photocatalyst efficiencies” chart.

This initiative would provide an important platform for establishing standard testing protocols for photocatalytic water splitting and for improving the solar-to-hydrogen conversion efficiency in practical applications.

This work was supported by the National Natural Science Foundation of China.

Resources

• Zhiliang Wang, Takashi Hisatomi, Rengui Li, Kazuhiro Sayama, Gang Liu, Kazunari Domen, Can Li, Lianzhou Wang (2021) “Efficiency Accreditation and Testing Protocols for Particulate Photocatalysts toward Solar Fuel Production” Joule doi: 10.1016/j.joule.2021.01.001